Updated the WordPress Amazon Associate Plug-in to 1.70 and it promptly crashed my WordPress. It prompted the following error when trying to access the WordPress platform
Fatal error: Call to undefined function wp_get_current_user() in /xxxxxx/wp-includes/capabilities.php on line 1039
Found a solution to the above fatal error caused by Amazon Associate Plug-in 1.70. Simply edit wp-includes/capabilities.php. Add in the following after the comments and before the first class definition.
Save the file and access your WordPress. It should work!
If it does not work for you, simply move the Amazon Associate Plug-in (wordpress-amazon-associate) out of wp-content/plugins. You are effectively removing the problematic plugin.